James mahony



V J. MAHONY, SteamBoiler Furnace.

Np. 225,402. Patented Mar. 9, 183-9..

N4 FEJIERS. PHOTO-LITHOGRAFHER. WASHINGTON D. G.

PATENT OFFICE.

JAMES MAHONY, OF NEWPORT, RHODE ISLAND.

STEAM-BOILER FURNACE.

SPECIFICATION formingpart of Letters Patent No. 225,402, dated March 9, 1880.

Application filed November 24, 1879.

To all whom it may concern: i

Be it known that I, J AMEs MAHONY, of New. port, in the State of Rhode Island, have in vented certain new and useful Improvements relating to Steam-Boiler Furnaces, of which the following is a specification.

The improvement may be used with agreat diversity in the form of the boiler; but 1 prefer the'horizontal tubular.

I arrange the gratewith a space behind it, a portion of which space allows air to pass up into a peculiarly-formed hollow bridge of metal or fire-brick, or both, and another portion serves to pass up cold air to cool the tubes when desired, and at other times serves as a receptacle for fine cinders and like solid matter which are there deposited and can be taken out at intervals. Thebridge is of wedge shape, the thickest portion uppermost. It extends quite across the furnace, and is corrugated in lines extending up and down its front and back faces. Its top is rounded in cross-section.

7 All the top and a portion of the front face are perforated, to deliver its contained air in fine streams into the combustible gases in the furnace.

The lower edge or mouth of the bridge, as also the space behind it, is controlled by means which allow the passage of the air to be free or restrained, at will. When the space behind is first opened it drops any ashes or cinders which may have accumulated. If it is then promptly closed, the space serves usefully to receive the solid matter brought over by the draft without affecting the latter; but if it remains open it allows a current of air to be drawn upward behind the bridge, which diminishes the draft of the fire, and by supplymg cool air to flow up behind the bridge and pass through the tubes tends greatly to cool the boiler and prevent the useless production of steam. This condition is important in locomotives when stopping at stations, and in all boilers where a hot fire exists which it is desired shall not for a period generate any steam.

The accompanying drawings form a part of this specification, and represent what I consider the most desirable mode of carrying out the invention.

Figure 1 is a side sectional view of my device in its place. The remaining views represent details detached, Fig. 2 being a top view of the air-distributer, and Fig. 3 a perspective view of the same, looking from the right in Fig. l.

Similar letters of reference indicate like parts in all the figures.

A is the boiler, certain parts being indicated by further marks, as A A. The tubes are marked a. The water-legs, as they are sometimes calledthe thin water-spaces which extend down around-the furnace-are marked A.

W is the grate, and W the cross-bars or bearers on which the grate and the fuel thereon are supported. The grate is a little above the lower edges of the water-legs A. The bearer at the rearor back edge of the grate extends down to the level of the base of the waterlegs, and forms a hinged support for G, a stopvalve, worked by a lever or other convenient means, (not shown,) which controls the aperture to the bridge.

The main body ofmy hollow bridge is marked D, certain parts being marked by additional characters, as D D The lower edge, D, is open, except when it is closed by the hinged flap or valve 0. The upperedge, D ,is rounded in cross-section and is closed, except that that part, as also the front face, D and the back face, D", is or may be perforated by small holes cl. I have not contemplated making any of these holes (1 on the back face, by which I mean the face D which is presented toward the tubes a but that part can be perforated, if desired in any case. The top D and the front face, D are thickly perforated.

When the boiler is in use making steam, with a thick fire on the grate W, the hot gases arising therefrom are combustible if air can be presented. I

My device presents air in small streams highly heated, and in a manner which may be perfectly controlled by the valve G.

My device can be easily introduced and removed by removing the grate and the back bearer. It may be worked by leaving the sides open, so that a thin sheet of air will flow out along the joint between each sheet D and.D and the inner metal (sometimes called the internal fire-box) of the boiler. I prefer, however, to make the device a little narrower than the furnace, and to close the sides, as indicated by D in Fig. 3. The entire bridge D may be made of boiler-iron, cast-iron, or other cheap and durable metal, or it maybe made of fire brick or other refractory earthy matter; or it may be metal faced on the hottest portions with fire-brick.

The bridge D may be set at various inclinations; but itis important to hold its front face sufficiently back to allow of convenient firing through the door. I prefer about the inclination shown, as it gives a just sufficient space behind the bridge at the top to allow the hot gases to descend freely to the lowermost tubes, at, and make the Whole effective. The space hehind at the base may be very narrow, but must allow a sufficient upward flow of air to relieve the draft and to cool the boiler when requlred. The other function of this space-the collection and retention of solid particles carried over the bridge-may be served by a very limited space; but in such case the valve E must be often opened for a moment to allow the dust' to drop out.

The rounded form of the top D allows the streams of air through its perforations to be well distributed into the gases passing over it. The corrugations allow the device to expand and contract without injury to itself or the rigid sides of the tire-box in which it is contained. It may fit closely within the furnace, or may be blocked or wedged fast by pieces of fuel or clinker each side without involving difficulty.

There is no objection to the device expand-v ing up and down, so I do not deem it necessary to corrugate in both directions; but that can be done, if desired.

I provide for forcing in the air so as to give a little pressure in excess of the ordinary atmosphere. This is done by means of jets of live steam.

G is a small pipe leading from the steamspace in the boiler, controlled by a valve, H,

and extending across near the bottom of my bridge, with nozzles g directed upward. Whenever it is desired to urge the induction through my bridge a partial or complete opening of the valve H will cause strong but minute jets to issue from the several nozzles g, and by their well-known action to drag in liberal quantities of fresh air with them. The steam thus mingled with the air is decomposed in the furnace, and its hydrogen aids the combustion. The effect of steam thus mingled in small quantities is found beneficial in most cases. The valve H gives the attendant power to let it in so gently as to act without materially increasing the air-flow, if desired.

The construction allows of expanding and contracting in the vertical direction indefinitely. Modifications may be made. Lugs may be provided in the interior of the furnace to hold it in a rigid position, or devices may be employed to hold it at the bottom, which may allow it to be easily adjusted at different angles. The bridge may be made in sections properly fastened together, to allow any part to be renewed when warped or cracked by the heat Without removing the whole. Other modifications may be made by any good mechanic without departing from the principle of the invention.

I claim as my invention- The hollow fire-bridge having rounded and corrugated top and corrugated sides, perforated and arranged in an inclined position in the fire-box in front of the tubes at of a tubular boiler, A, the steam-connection G, and blower g, combined with said boiler and controllingvalves 0 E, as and for the purposes set forth.

In testimony whereof I have hereunto set my hand this 19th day of November, 1879, in the presence of two subscribing witnesses.

JAMES MAHONY. Witnesses:

THOMAS D. S'IETSON, CHARLES C. STETsoN. 

